Holder for a culture sample

ABSTRACT

A culture sample holder, which can be placed in a culture apparatus comprises an inner holder, which is hollow inside, and an outer holder, which is hollow inside. The inner holder is insertable in the outer holder to an assembly of the inner holder and outer holder where the outer bottom of the inner holder faces the inner bottom of the outer holder, thus forming a space for a culture sample to be placed between the outer bottom and the inner bottom. The inner holder comprises a protrusion and the outer holder comprises a recess in its side wall. The protrusion is placed in a first position of the inner holder inside said recess in the side wall of the outer holder and in a second rotated position of the inner holder, the protrusion is placed in the outer holder outside the recess at a higher position with respect to the first position.

FIELD OF THE INVENTION

The present invention relates to a culture sample holder, which can be placed in a culture apparatus, for example in a well of a well plate, and comprises means for fixing the culture sample in the holder.

BACKGROUND OF THE INVENTION

The purpose of the culture sample holder is to support an in vitro cell or tissue culture sample when it is placed in a liquid medium in a culture apparatus, and to act as a kind of a carrier, by means of which the culture sample can be inserted in the medium and taken out of it. To implement this, the holder comprises means for fixing the culture sample.

The liquid medium is normally in the well of the well plate, and it contains nutrients etc. essential for the cells of the culture. For example, holders are known in which the culture sample is a microporous membrane attached to the open bottom of a cylindrical holder. U.S. Pat. No. 5,710,043 discloses an arrangement, in which a holder and, correspondingly, a microporous membrane at its bottom can be placed at different heights in a well by means of suspending means protruding from the wall of the holder, wherein corresponding steps are formed on the inner wall of the well. An arrangement which applies a corresponding principle and in which the holders are suspended not on the wells but from openings in a plate placed above the well, is disclosed in international publication WO 2006131123 (corresponding US publication 2008194017). Publication US 2008076170 (Annala et al.) discloses a holder, to whose lower end a membrane-like cell culture sample is attached by means of a locking ring, and the holder can be adjusted in a stepless manner to a desired height position by means of elastic gripping means supported against the inner wall of the well.

The problem is that the culture samples may vary in size due to the structure, the origin of the tissue, and the intended use of the sample, and membrane-like supports (substrates) are not necessarily the only ones for cells and tissues. FIG. 3 in US 2008076170 shows an arrangement, in which a thicker culture sample can be kept against the bottom of the well by means of a holder supported to the inner wall of the well.

Particularly in the case of small and/or multiple samples, it is advantageous to fix them quickly and easily in the holders which are placed in a culture apparatus, for example in wells of a well plate, in such a way that the samples (cell culture samples) come into contact with a liquid medium in the culture apparatus. However, the problem arises that the samples may adhere to the bottom of the well or corresponding culture vessel, and they may be difficult to detach. Another problem is that when a detached sample has been inserted in a well that contains liquid, it may move and turn upside down, unless it is kept in position.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a holder, by means of which the samples can be quickly inserted in a culture vessel of a culture apparatus (such as a well of a well plate) but which does not have said drawbacks. To attain this object, the holder according to the invention is primarily characterized in that the holder comprises an assembly of an inner holder, which is hollow inside, and an outer holder, which is hollow inside, wherein the inner holder can be inserted inside the outer holder in such a way that the outer bottom of the inner holder faces the inner bottom of the outer holder, thus forming a space for the culture sample to be placed between said bottoms, and that the inner holder comprises a protrusion which in a first position is placed inside a recess in the wall of the outer holder, and, in a second position where the inner holder is rotated around an axis running in the direction of insertion of the holders, the protrusion is placed in the outer holder outside the recess, at a higher position with respect to the first position.

When the holders are nested in this way, the culture sample can be fixed between their bottoms by inserting first the sample inside the outer holder, on top of its inner bottom, and then the inner holder is inserted inside the outer holder and above the culture sample. By selecting the position, the distance between the bottoms of the holders can be adapted to the dimensions of the culture sample, particularly its thickness. The holder assembled in this way can be placed, as a self-contained holder, into a cell culture apparatus, for example a well of a well plate, in contact with the liquid medium therein. The liquid medium comes into contact with the cell or tissue culture sample via an opening at the bottom of the outer holder. Furthermore, the culture sample can be accessed and observed through an opening at the bottom of the inner holder, and if necessary, substances essential for the culture sample can also be provided through the opening. The assembled holder prevents the culture samples from floating and turning about in an uncontrolled way, and facilitates their removal from the culture apparatus. The bottom of the outer holder is placed between the culture sample and the bottom of the culture vessel (for example, a well), and prevents the culture sample from sticking during the culturing.

Advantageously, the inner holder and the outer holder are provided with protrusions and recesses respectively in pairs so that, in the first position, a pair of protrusions is aligned with a pair of recesses and, in the second, rotated position, the pair of protrusions is left outside the pair of recesses. When two protrusions are suitably spaced from each other, the inner holder can be placed in a more stable way in both the first and the second position.

In an advantageous embodiment, the recess of the outer holder is a slot extending through its side wall and being open on top, and the higher position, in which the protrusion of the inner holder is placed in the second position, is the upper edge of the side wall adjacent to the slot. This provides a simple structure, and even small holders can be implemented.

The bottoms of the holders are advantageously provided with openings, through which liquids can flow.

In yet another advantageous embodiment, the inner holders are aligned in a row at regular intervals from each other in such a way that they are connected at their top parts by horizontal connecting elements, wherein weakenings are preferably provided between the top parts of the holders and the connecting elements, for detaching single holders. This kind of a “strip” of inner holders can be inserted as such in the outer holders already existing in a row of wells of the culture apparatus, in such a way that the inner holders fit inside the outer holders, on top of the culture samples already placed in them, or the strip, where the outer holders and the samples are already fixed, can be placed into the row of wells in one go. It is a prerequisite that the spaces between the inner holders in the strip are dimensioned according to the spaces between the wells; in other words, when the culture apparatus is a well plate, they can comply with the well pitch of the standard well plate. However, single holders can be detached from such a strip to be used one by one, if desired.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described with reference to the appended drawings, in which

FIG. 1 shows a series of inner holders from below,

FIG. 2 shows the same series from the side,

FIG. 3 shows the same series from above,

FIG. 4 shows the same series in a cross-section in the plane A-A of FIG. 3,

FIG. 5 shows the series of outer holders, seen from above,

FIG. 6 shows the same series in a cross-section in the plane A-A of FIG. 5,

FIG. 7 shows series of inner holders and outer holders with a slightly different shape in a perspective view,

FIG. 8 shows the inner and outer holders of FIG. 7 nested in the first position,

FIG. 9 shows the holders of FIG. 7 nested in the second position, and

FIG. 10 shows the use of the assembled holder in a well of a well plate.

DETAILED DESCRIPTION OF THE INVENTION

In this description, the terms “height”, “horizontal” and corresponding terms, as well as the relative terms “up”, “down” and corresponding terms refer to the situation of use of the holder and denote the position in relation to the liquid level which settles according to the gravity. Thus, horizontal means parallel to this surface and the height refers to the dimension perpendicular to this surface.

The holder to be assembled from parts and placed in a well, or the like, of a cell culture apparatus comprises an inner holder 1 and an outer holder 2, each having a vertical side wall that forms a closed periphery in the horizontal cross-section and also determines the shape of the piece in the horizontal cross-section perpendicularly to the height direction. The pieces can be characterized as cup-shaped pieces which are hollow inside and comprise a mouth that is open at the top, and a bottom. The external dimensions of the inner holder 1 are designed so that it fits inside the outer holder 2. In the case of cylindrical pieces, the outer diameter of the horizontal cross-section of the inner holder 1 is smaller than the inner diameter of the horizontal cross-section of the outer holder 2. When the holders 1, 2 are placed together in the well of the cell culture apparatus with a sample (for example a cell or tissue culture sample) between them, they come in a vertical position in such a way that the inner holder 1 is inside the inner wall of the outer holder 2 and the outer bottom of the outer holder is on top of the bottom of the well of the cell culture apparatus.

The structure that keeps the sample in its place consists of the inner holder 1 that is hollow inside, and the outer holder 2 that is hollow inside. The holders can be nested in two different positions, in which the distance between the bottoms of the holders 1, 2 is different. In FIGS. 1 to 9, the holders are shown in series formed of successive holders connected one after the other: the series of the inner holders 1 by horizontal strips or connecting elements 4 connecting the holders one after the other, and the series of outer holders 2 to a single elongated strip 6 by short connecting elements 6 a extending sideward from the strip. In this way, several holders 1, 2 can be joined together for manufacture and sales, but they can be detached from their series to single holders, for which reason the elements that connect the holders are provided with weakenings. In the following, the operation of the invention will be described, when the inner holder 1 and the outer holder 2 are detached, although the holders 1, 2 shown in FIGS. 1 to 9 are joined in series of their own.

The outer holder 2 that comes further down in the well of the well plate, is provided with two slots formed in the side wall and open at the top, spaced by a given angular distance in the peripheral direction, in such a way that these slots form recesses 2 a at the top edge of the holder, extending towards the bottom. In a corresponding way, the inner, upper holder 1 comprises protrusions 1 a spaced by the same angular distance as the recesses 2 a of the outer holders. These protrusions extend radially to the area of the side wall of the outer holder 2 when the holders are aligned in such a way that their vertical central axes coincide.

When the inner holder 1 is placed in the first position inside the outer holder 2 from above in the direction of their axis L extending in the height direction (FIG. 8), the protrusions 1 a of the inner holders 1 are received in the recesses 2 a of the outer holder 2. On the other hand, when the inner holder 1 is turned 180° in the direction of its periphery, the inner holder 1 will be placed inside the outer holder 2 in a second position, in which the protrusions 1 a are supported to the upper edge of the side wall of the outer holder 2, outside the recesses 2 a, and the inner holder 1 rises in the outer holder 2 higher than the first position (FIG. 9).

A prerequisite for this operation is that the angular spacing of the recesses 2 a and the protrusions 1 a, respectively, on the periphery of the holder is smaller than 180°; that is, the recesses 2 a and the protrusions 1 a must not be on diametrically opposite sides in their respective holders. A suitable angular distance between two protrusions and recesses, respectively, is sufficiently large so that the position of the inner holder is sufficiently stable, for example between 120° and 160° (measured from the vertical central lines of the protrusions and the recesses).

By the above-mentioned operation, it is possible to change the distance between the bottom of the inner holder 1 and the bottom of the outer holder 2, for placing the cell or tissue culture sample between the bottoms and holding it in its place. In the first position, in which the protrusions 1 a are in the recesses 2 a of the outer holder 2, the bottoms of the holders 1, 2 touch each other. The distance between the bottoms can be changed by lifting the inner holder 1, wherein the protrusions 1 a move in the height direction in the recesses 2 a, but the inner holder 1 can still not rotate in the direction of the periphery. In this position, the spacing between the holders in the height direction is adapted steplessly to the culture sample dimensions in the same direction while the holders 1 a are non-rotatable with respect to each other. In the second position, in which the bottoms of the protrusions 1 a rest on the upper edge of the side wall 2 of the outer holder, the distance between the bottoms is constant. In this second position, in which there is a constant distance between the bottoms of the holders 1, 2, thicker culture samples can be placed between the bottoms than in the first position. This second position can be used particularly for placing such sensitive and fragile materials which do not stand pressure.

As shown in the figures, both the inner upper holder 1 and the outer lower holder 2 are provided with an opening 1 b and 2 b, respectively, at the bottom. Thus, the liquids can flow freely from the well of the culture apparatus through the opening 2 b of the bottom of the outer holder 2 to the cell or tissue culture sample, and liquids can be added to the cell or tissue culture sample and the sample can be examined through the opening 1 b of the bottom of the inner holder 1.

FIG. 10 shows a vertical cross-section of the location of the cell or tissue culture sample 3 itself between the outer bottom (lower end surface) of the inner holder 1 and the inner bottom of the outer holder 2, when the holders 1 2 are nested and their assembly is placed in a well 5 of a culture apparatus, such as a well plate. The figure shows the holders 1, 2 in a position in which the protrusion 1 a is received in the recess 2 a. The figure also shows how the vertical extension of the side wall of the inner holder 1, the connecting element 4 being connected to the upper end of the extension by means of a breakable weakening, provides a small handle or gripping element for placing the inner holder 1 inside the outer holder 2.

The series of inner holders 1 which is shown in FIGS. 1 to 9 and in which the holders are connected to each other at the top by means of horizontal connecting elements 4 to form a row, can be used as such in a row of wells in a culture apparatus, where the outer holders 2 and the culture samples 3 are placed, when the spacing between the holders 1 corresponds to the well pitch. It is also possible to detach shorter series of several holders 1 or single holders 1 from the series. When the outer holders 2 are connected together from below as shown in FIGS. 1 to 9, the series of outer holders stand well erect on a flat surface when the samples are placed in them. Such series can also be used as such in culture apparatuses having a uniform culture space (culture vessel) and no separate wells, without a need to detach the holders 2 from each other. The outer holders 2 can also be connected together to form a row in the same way as the inner holders 1, by means of horizontal connecting elements extending between the holders 2 and connecting the holders to each other at the top. The connecting elements are brought at a sufficient height so that the holders 2 left below the level of the connecting elements fit into the wells of the culture apparatus unobstructed by the connecting elements.

In FIGS. 1 to 9, the number of holders 1, 2 in the series is eight, which is a common number of wells in a single row of a well plate. The number may also be different.

Both the inner holders 1 and the outer holders 2 and the elements connecting them can be made by injection moulding from a suitable plastic.

The term “culture sample” used in the description above can be understood in a wide sense, and it refers to samples with a support (for example a porous piece) for the attachment and growth of cells or tissue, or samples in which the cells or the tissue exist as such. It is also possible that the support to be fixed between the holders does not contain cells or tissue at the beginning, but these all grow later in the support when the holder is in the culture apparatus. The culture sample may be intended for medical diagnosis or research or other scientific research. 

1. A culture sample holder which can be placed in a culture apparatus, comprising: an inner holder, which is hollow inside and comprises a bottom that defines an outer bottom, an outer holder, which is hollow inside and comprises a bottom that defines an inner bottom, the inner holder being insertable in the outer holder in a direction of insertion to an assembly of the inner holder and outer holder where the outer bottom of the inner holder faces the inner bottom of the outer holder, thus forming a space for a culture sample to be placed between the outer bottom of the inner holder and the inner bottom of the outer holder, the inner holder further comprising a protrusion and the outer holder further comprising a side wall and a recess in said side wall, the protrusion being placed in a first position of the inner holder inside said recess in the side wall of the outer holder and, in a second position of the inner holder rotated around an axis running in the direction of insertion, the protrusion is placed in the outer holder outside the recess at a higher position with respect to the first position.
 2. The holder according to claim 1, wherein the inner holder and the outer holder are provided with protrusions and recesses, respectively, in pairs so that, in said first position, a pair of protrusions is aligned with a pair of recesses and, in said second, rotated position of the inner holder, the pair of protrusions is left outside the pair of recesses.
 3. The holder according to claim 1, wherein the recess of the outer holder is a slot extending through the side wall of the outer holder and being open on top, and the higher position, in which the protrusion of the inner holder in said second rotated position of the inner holder is placed, is an upper edge of the side wall adjacent to the slot.
 4. The holder according to claim 2, wherein the recesses of the outer holder are slots extending through the side wall of the outer holder and being open on top, and the higher position, in which the protrusions of the inner holder in said second rotated position of the inner holder are placed, is an upper edge of the side wall adjacent to the slots.
 5. The holder according to claim 1, wherein both the inner holder and the outer holder comprise an opening at the bottom.
 6. The holder according to claim 2, wherein both the inner holder and the outer holder comprise an opening at the bottom.
 7. The holder according to claim 1, wherein the inner holder forms together with other similar holders a series, where the inner holders are aligned in a row at regular intervals from each other and connected at their top parts by horizontal connecting elements.
 8. The holder according to claim 7, wherein weakenings are provided between the top parts of the inner holders and the connecting elements for detaching single inner holders from the series. 